Method of tempering leather



NOV. 28, 1944. A, J, WELLS 2,363,715

` METHOD oF TEMPERING LEATHER oiginal Filed Jan. 25; 1941 @MKM Patented Nov. 28, 1944 METHOD F TEMPERING LEATHER Adoniram J. Wells, Wilmington, Del., assignor to B. B. Chemical Co., Boston, Mass., Aa. corporation oi' Massachusetts v Original application January 25, 1941, Serial No. 375,951. Divided anlsigsipplication February 3 Claims. (Cl. 12-146) ll, 1942, Serial No.

' This invention consists in a method of tempering leather Without'staining the grain surface thereof or removing any of the tanning substances therefrom.` It is known that some solid tanning substances with which leather is loaded are soluble in water and that immersion of leather in Water results in washing away some of them. Even if water comes into contact with the grain surface of leather otherwise than by immersing the latter, the water-soluble substances are reduced to a migratory condition and rin consequence thereof staining of the grain surface is likely to result, particularly if that surface is spattered without being entirely wet with water.

Again, it is known that leather can be tempered with warm water-vapor without water in the liquid state, and that such treatment will not produce stains. Nevertheless, if convection alone is the only force by which water-vapor is transferred from its source to the leather, the speed of transfer is so slow that much time is required to accomplish a useful degree of temper.

With these considerations in view, an object of the method herein set forth is to utilize the advantages of tempering with water-vapor and at the same` time speed the tempering process. This may be accomplished with an apparatus of the type set forth in my application for Letters Patent of the United States, Serial No. 375,951, filed January 25, 1941. The present application is adivision of that identified above.' In describing the method to which the present application is directed, it will be assumed that unattached leather soles are the articles of work to be tempered, although it is to be understood that to the wires 22 to expose` their surfaces to the the utility and advantages of the method are not limited to the treatment of soles. l

In the drawing,

Fig. 1 is a sectional elevation of apparatus adapted for use in practising the method of the present invention; i

Fig. 2 is ya section on the line II-II of Fig. 1; and

Fig. 3 is a bottom shown in Figs. 1 and 2.

The soles to be tempered are placed in a chamber l0 that also contains a body'of water l2. The water is heated by an immersion heater I4 coni trolled by VVa thermostat I6 to furnish a supply planv view of the air pipe Vof vapor at a temperature of about 140 F. in-

dicated by a thermometer I8 and the soles 20 are supported above and out of contact with the water and out of contact with each other on .'wires 22 and wires 24 extending at right angles vapor. If nothing more were done a long period of treatment would be required produce a useful state of temper because thequantity of vapor supplied to the soles by convection alone would be small and the circulation of vapor between and around the soles would be slow.

To accelerate the tempering process the quantity of vapor is' increased without increasing its temperature, and its circulation around the so'les` i is accelerated by emitting a forced draft of air at high velocity through perforated pipes 2B located in the body of water belo'w its surface and releasing the used air and surplus vapor to the atmosphere through a restricted vent 28 above the soles. I'he restriction of thevent is to prevent the chilling effect of atmospheric air that might otherwise enter the chamber above the soles.

The air forced into the body of heated water is divided into many small jets by the perforated pipes 26 to insure a large number of small bubbles and a high degree of absorption of heat and vapor by the air. water thus produced increases the vapor output thereof. At the same time the bubbles of air absorb heat from thewater and become substantially saturated with vapor. Then, since a large volume of vapor-charged air flows under forced draft from the Water below the soles to the restricted vent above them it causes a large quantity of vapor to ow on the surfaces of the soles located in its path. f

The boiling producedby emitting air under pressure in the water also produces many globules of water so small as to be carried along in the stream of vapor-charged air which flows at considerable velocity. If these globules of water were spattered on the grain sides of thersoles they would produce stains. Therefore, to guard against that result the method includes the step of filtering the stream of vapor and air to arrest the globules atpoints between the body of water and the soles without appreciably diminishing the vapor content of the stream. This filtering may be accomplished by arranging a series of non-absorbent bailies in the path of the stream to divide the latter into smaller streams and to deflect these. The bailles may comprise a pair of perforated plates 30, the holes in one plate being in staggered relation to those ofthe other.` i precipitated against the" latter while the air and Moreover, the boiling action of the that of the vapor little, ifL

and maintaining a tempering atmosphere for leather which consists in heating a body of water to a suitable predetermined temperature substantially below lthe boiling point, forcing air at room temperature through said body to cause the air to be heated and laden with water-vapor, illtering the vapor-laden air to remove water in liquid form to provide a water-free tempering atmosbut it is desirable to temper their grain sur-V phere, maintaining its temperature constant to prevent condensation of vapor, passing said atmosphereinto a yleather-treating chamber and I `permitting a restricted escape of said atmosphere six soles at once will be capable of keeping pace with the output of a commercial sole-conforming machine. l

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

v1. `Thai; improvement in methods of producing and maintaining a tempering atmosphere for leather which consists in heating a body of water to a suitable predetermined temperature substantially below the boiling point, forcing air at room temperature through said body of water to cause the air to be heated and laden with water-vapor, removing water in liquid form from thel vaporladen air to provide a water-free tempering atmosphere, passing said atmosphere through a work-treating chamber and maintaining it against condensation by continuously supplying the chamber with further quantities of atmosphere at a rate suillcient to maintain a continuous current thereof through the chamber.

2. That improvement in methods of producing.

therefrom, and maintaining said atmosphere against condensation by continuously supplying the chamber with further quantities of said atmosphere at a' rate at least equal to the rate of escape therefrom.

3. That improvement in methods of producing and maintaining a tempering atmosphere for soles which consists in heating a body of water to a predetermined temperature sufficient to heat air passedtherethrough to approximately 140 F., forcing air at the normal temperature through said body of water to cause the air to be heated and laden with water-vapor, removing from the vapor-laden air water in liquid form to provide a water-free tempering atmosphere, passing the said atmosphere through a sole-treating chamber having an opening to the outer air, and maintaining said atmosphere against condensation by continuously supplying the chamber with further quantities of said atmosphere at a ratesufflcient to maintain a continuous current thereof through the chamber. i

ADONIRAM J-. vWELLSrfffff -i 

